One possible guess — The bolts should be a tight fit in the holes. On mine, I had to drive the bolts in with light taps with a hammer. If the bolts fit too easily in the holes, there could be a small amount of motion at the joint. This motion could cause the washers to wear into the spar surfaces slightly. That would result in a slight loss of tension load in the bolt and the apparent loss of torque. --
Bryan Martin
N61BM, CH 601 XL,
RAM Subaru, Stratus re-drive.
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Quote:

On Apr 26, 2017, at 8:30 PM, BobbyPaulk(at)comcast.net (BobbyPaulk(at)comcast.net) wrote:
Paul,
The nuts have not backed off.
I had the paint dobs to make sure that they did not move.
I don't know what is happening except maybe the metal is bending.
Thanks for your input.
Bobby

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Is it possible that you over torqued the bolts? It would have to be a pretty large over torque, so it’s hard to think it’s really the cause, but if they are over torqued just enough the bolt could “relax” and loosen just a bit. This is an intrinsic failure mode of steel and one of the things that makes it more forgiving to work with than aluminum. To be safe, I’d replace all the bolts and check the calibration of the torque wrench when replacing.
If you ever find the cause, I’m sure many of use would like to know what happened.

Ron

Quote:

On Apr 28, 2017, at 8:42 AM, BobbyPaulk(at)comcast.net (BobbyPaulk(at)comcast.net) wrote:
Brian
Thanks for the reply.
My bolts were very tight. I had to make a short bullet shaped bolt with no head to push thru before the threaded bolt would go.
I lined up all the holes with temporary bullet shaped bolts and replaced them one at a time with no weight on the wing.

Bobby

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One other thing to consider which is often a reason bolts "lose torque" is that there was some contamination between the pieces of aluminum when the bolts were first torqued. Then over time the contamination changes character and things have to be tightened again. Even a fraction of a thousands of dirt (hard to see) can cause trouble. A .001 inch change results in about 10 degrees of rotation.

On 4/28/2017 8:57 AM, Ronald Steele wrote:

Quote:

Is it possible that you over torqued the bolts? It would have to be a pretty large over torque, so it’s hard to think it’s really the cause, but if they are over torqued just enough the bolt could “relax” and loosen just a bit. This is an intrinsic failure mode of steel and one of the things that makes it more forgiving to work with than aluminum. To be safe, I’d replace all the bolts and check the calibration of the torque wrench when replacing.
If you ever find the cause, I’m sure many of use would like to know what happened.

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